Nowadays, temperature control is basically based on air conditioner and electromagnetic waves. However, both methods suffer from problems of energy waste and low energy efficiency.
Taking the air conditioner as an example, the air conditioner regulates the air temperature inside the room by undergoing heat exchange with the air inside the room. In practice, when the room temperature needs to be risen up, an air conditioner will heat up the air inside the room and release the heated air into the room, which will heat up all objects inside the room and consequently lead to a waste of energy, e.g., the refrigerator that shall be kept cold is also heated. In addition to low efficiency, air conditioner also suffers from another problem of long response time. It can only slowly heat up the certain space as a whole.
Another technology involving heating is, for example, the “bathroom-master”, which can use the electromagnetic wave generated by high temperature materials to heat up the subject. The fact is that the bandwidth of the electromagnetic wave generated by the bathroom master is large, generally bigger than 100 nm and the to-be-heated subject has low absorbing coefficient to some wavelength of the electromagnetic wave, which results in a waste of energy since some energy is wasted to produce the electromagnetic wave that is difficult to be absorbed by the to-be-heated object. Additionally, the bathroom master also generates massive visible light and ultraviolet, of which the visible light will cause glaring, and make human eyes uncomfortable. The ultraviolet may even cause injury to human bodies and therefore unhealthy.
Another problem of using electromagnetic wave for heating is that the emission direction and beam angle cannot be adapted to the shape of the to-be-heated object, causing a portion of the electromagnetic wave is not used to heat up the to-be-heated object and therefore wasted. For example, the bathroom floor and the wall are heated as well.
It is because this kind of drawbacks existed in the current heating method and devices, a kind of more efficient heat generating device, which will target the to-be-heated object to raise its temperature while avoid heating up untargeted object or space is highly wanted so as to ensure higher energy efficiency.